WHY are so many virtually uninhabited cities still being built in China?

On last night's Dateline on SBS ONE, Asia correspondent Adrian Brown returned to update one of the program's most watched stories. Here he reveals the rather mixed response to the media attention:

China, frankly, has grown weary of endless reports about its severely under populated cities. That's why the provincial government of Inner Mongolia refused to issue me with an invitation letter. Maybe they'd seen my earlier Dateline report on China's Ghost Cities.

Anyway, the coaxing and cajoling failed, and no letter was forthcoming. So in the end I had to visit Ordos unofficially … it's reputedly the biggest ghost city of them all.

Arriving, I was struck by the similarity with North Korea's capital, Pyongyang. Wide, empty boulevards. Grandiose architecture with confused themes. And an eerie shortage of people. On the smooth, straight highway into the city we saw only two other vehicles. And yet this was 8.30am … rush hour in most cities.

My tour guide took me to the central plaza, which is more than two and a half kilometres long and about 200m across. And all this for a city with a population of just 140,000!

Ordos is one of China’s most impressive ghost cities. Picture: Dateline SBSSource:Supplied

At times you have to pinch yourself and say, 'Yes, it's real'. Our cover was blown within a few hours of arriving though. My guide was suspicious of my endless questions about why the place was so empty. Eventually her boss turned up, along with an official from the Public Security Bureau.

After checking my passport, their suspicions were confirmed … no journalist visa. Strangely I was told that while this meant I did not have permission to talk to anyone, I could continue filming.

The roads are eerily empty. Picture: Dateline SBSSource:Supplied

Property bubble?

On the outskirts of Ordos lies the new city of Kangbashi, built to accommodate a million people. And while many of its properties have been sold, the city is still largely empty. Most of these homes were bought for investment during a mining boom that's now well and truly over.

A decade ago this part of Inner Mongolia was one of the richest areas in China, says urbanisation expert Tom Miller.

"China is a very, very large country and it doesn't make sense to talk about a single bubble," he explains.

"Imagine China as bubble wrap. Some of those bubbles within it might burst. Ordos is one example. The bubble did burst there a couple of years ago."

But perhaps there is method in this construction madness. China says it needs to move more than 400 million people from the countryside into the cities in the next 10 years. No country in the world is witnessing urbanisation of this size. It's a social experiment on a grand scale.

Eventually, it was clear I had overstayed my welcome and was told I would be driven to the airport … just four hours after arriving. I was being politely deported from China's biggest ghost city. I joked to my guide, "but don't you need people."

"Yes, but not like you," she replied sharply.

A big city, with hardly a soul in sight. Picture: Dateline SBSSource:Supplied

700 mountains levelled

More than 700km to the south, the welcome could not have been more different. The officials behind Lanzhou New Area, a new city being carved out of the mountains of Gansu Province, seemed overjoyed to receive us.

I was encouraged to pose for pictures with the deputy mayor and other senior local party members. I was also invited to give my views on China's newest city to the local media … less than two hours after arriving in Lanzhou.

In this lunar landscape they are levelling 700 mountains to build a 130,000ha metropolis from scratch. Up to a million people will eventually move in.

The new city's Deputy Mayor, Guo Zhiqiang, told me the city will not repeat the mistakes of Ordos.

"Lanzhou New Area will definitely not become an empty city, or a ghost city. Essentially, it will be a fantastic, fully equipped city. It will be a beautiful city. It can lift the residents' standard of living," he told me.

Homes in the sky

On the outskirts, I met some of the rural migrants from the city's sprawling hinterland, who are waiting to move into their new homes "in the sky."

They are farmers, mostly and have had no say in their relocation. But with government minders in ear shot, they all tell me in unison that they are glad to be moving. The process of demolishing their homes has already begun.

And it's a process taking place across the country as millions more prepare to make the move to the city.